Gentlemen,
Have a look at this video. He did at least one follow up which is even more interesting.
The upshot is that, for 12ga duck loads, shot stringing does not make a meaningful difference. The strings are short enough, and the shot is traveling fast enough, that nearly all the shot arrives on target, even with the bird flying at 40mph.
I would love to see this experiment done with the 410!
https://m.youtube.com/watch?v=fac-03JF3GA&ra=m